US10044281B2 - Bidirectional insulated DC/DC converter and smart network using the same - Google Patents
Bidirectional insulated DC/DC converter and smart network using the same Download PDFInfo
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- US10044281B2 US10044281B2 US15/021,907 US201415021907A US10044281B2 US 10044281 B2 US10044281 B2 US 10044281B2 US 201415021907 A US201415021907 A US 201415021907A US 10044281 B2 US10044281 B2 US 10044281B2
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- 230000002457 bidirectional effect Effects 0.000 title claims abstract description 36
- 238000004804 winding Methods 0.000 claims description 18
- NCGICGYLBXGBGN-UHFFFAOYSA-N 3-morpholin-4-yl-1-oxa-3-azonia-2-azanidacyclopent-3-en-5-imine;hydrochloride Chemical compound Cl.[N-]1OC(=N)C=[N+]1N1CCOCC1 NCGICGYLBXGBGN-UHFFFAOYSA-N 0.000 claims description 9
- 238000001514 detection method Methods 0.000 claims description 2
- 238000010586 diagram Methods 0.000 description 16
- 239000003990 capacitor Substances 0.000 description 9
- 238000000034 method Methods 0.000 description 8
- 230000007274 generation of a signal involved in cell-cell signaling Effects 0.000 description 7
- 239000000284 extract Substances 0.000 description 4
- 230000003111 delayed effect Effects 0.000 description 2
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 229910001416 lithium ion Inorganic materials 0.000 description 1
- 230000005389 magnetism Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
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Classifications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
- H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
- H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
- H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
- H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/33569—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements
- H02M3/33576—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements having at least one active switching element at the secondary side of an isolation transformer
- H02M3/33584—Bidirectional converters
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/42—Circuits or arrangements for compensating for or adjusting power factor in converters or inverters
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
- H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
- H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
- H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
- H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
Definitions
- the present invention relates to a bidirectional insulated DC/DC converter and a smart network using the same, and particularly to a bidirectional insulated DC/DC converter provided with two inverters coupled by an insulated transformer, and a smart network using the bidirectional insulated DC/DC converter.
- bidirectional insulated DC/DC converter including two inverters coupled by an insulated transformer (for example, see PTD 1 (Japanese Patent Laying-Open No. 2010-124549)).
- PTD 1 Japanese Patent Laying-Open No. 2010-124549
- the conventional bidirectional insulated DC/DC converter poses a problem that DC power cannot be stably transmitted and received in the case where the difference between the DC voltages of two DC power systems greatly varies.
- a main object of the present invention is to provide a bidirectional insulated DC/DC converter capable of stably transmitting and receiving DC power even when the difference between two DC voltages greatly varies, and a smart network using the bidirectional insulated DC/DC converter.
- a bidirectional insulated DC/DC converter serves to transmit and receive DC power between a first DC circuit and a second DC circuit, and includes: a first inverter configured to generate a first alternating-current (AC) fundamental wave voltage based on a first DC voltage received from the first DC circuit; a second inverter configured to generate a second AC fundamental wave voltage that is equal in frequency to the first AC fundamental wave voltage based on a second DC voltage received from the second DC circuit; an insulated transformer including a primary winding and a secondary winding configured to receive the first AC fundamental wave voltage and the second AC fundamental wave voltage, respectively, and insulated from each other; a pulse width setting unit configured to set a pulse width of at least one of the first and second AC fundamental wave voltages based on the first and second DC voltages such that a voltage difference between the first and second AC fundamental wave voltages is smaller than a predetermined value; a phase difference setting unit configured to set a phase difference between the first and second AC fundamental wave voltages such that a desired DC power is transmitted and received
- a pulse width of at least one of the first and second fundamental wave voltages is set such that the voltage difference between the first and second AC fundamental wave voltages is smaller than a prescribed value
- a phase difference between the first and second AC fundamental wave voltages is set such that a desired DC power is transmitted and received between the first and second DC circuits
- a control signal for each of the first and second inverters is generated based on setting results. Therefore, DC power can be stably supplied in a desired direction even when the difference between two DC voltages greatly varies.
- FIG. 1 is a block diagram showing the configuration of a bidirectional insulated DC/DC converter according to the first embodiment of the present invention.
- FIG. 2 is a circuit diagram showing the configuration of an inverter shown in FIG. 1 .
- FIG. 3 is a block diagram showing a main part of a control circuit shown in FIG. 1 .
- FIG. 4 is a diagram for illustrating the operation of a pulse width setting unit shown in FIG. 3 .
- FIG. 5 is another diagram for illustrating the operation of the pulse width setting unit shown in FIG. 3 .
- FIG. 6 is a diagram showing waveforms of two AC fundamental wave voltages shown in FIGS. 4 and 5 .
- FIG. 7 is a diagram for illustrating the operation of a signal generation unit shown in FIG. 3 .
- FIG. 8 is another diagram for illustrating the operation of the signal generation unit shown in FIG. 3 .
- FIG. 9 is still another diagram for illustrating the operation of the signal generation unit shown in FIG. 3 .
- FIG. 10 is a block diagram showing the configuration of a smart network according to the second embodiment of the present invention.
- FIG. 1 is a circuit block diagram showing the configuration of a bidirectional insulated DC/DC converter according to the first embodiment of the present invention.
- this bidirectional insulated DC/DC converter includes: positive voltage terminals T 1 , T 3 ; negative voltage terminals T 2 , T 4 ; current detectors IS 1 , IS 2 ; voltage detectors VS 1 , VS 2 ; capacitors C 1 , C 2 ; inverters 1 , 2 ; reactors L 1 , L 2 ; an insulated transformer 3 ; a control circuit 4 ; and drivers DR 1 , DR 2 .
- DC circuit 5 is connected to terminals T 1 and T 2
- DC circuit 6 is connected to terminals T 3 and T 4
- DC circuit 5 includes a DC power supply generating DC power and a load driven by DC power
- DC circuit 6 includes a power storage device storing DC power.
- the DC power supply may be a solar photovoltaic power generator, a wind power generator, and the like.
- the power storage device may be a LiPo (lithium ion polymer) battery, an electric double layer capacitor, and the like.
- the bidirectional insulated DC/DC converter When DC power is excessive in DC circuit 5 , the bidirectional insulated DC/DC converter supplies the excessive amount of DC power to DC circuit 6 . When DC power is insufficient in DC circuit 5 , the bidirectional insulated DC/DC converter supplies DC power in DC circuit 6 to DC circuit 5 . At this time, the bidirectional insulated DC/DC converter transmits and receives DC power regardless of whether a DC voltage Ea of DC circuit 5 and a DC voltage Eb of DC circuit 6 are high or low.
- insulated transformer 3 includes a primary winding 3 a and a secondary winding 3 b insulated from each other.
- Primary winding 3 a and secondary winding 3 b are identical in number of turns.
- Primary winding 3 a has one terminal connected to an AC terminal 1 c of inverter 1 through reactor L 1 and the other terminal connected to an AC terminal 1 d of inverter 1 .
- Secondary winding 3 b has one terminal connected to an AC terminal 2 c of inverter 2 through reactor L 2 and the other terminal connected to an AC terminal 2 d of inverter 2 .
- Inverter 1 has a positive voltage terminal 1 a connected to a positive voltage terminal T 1 through current detector IS 1 and a negative voltage terminal 1 b connected to a negative voltage terminal T 2 .
- Current detector IS 1 detects a DC current that flows between inverter 1 and DC circuit 5 , and feeds a signal showing the detected value to control circuit 4 .
- Voltage detector VS 1 detects DC voltage Ea between terminals 1 a and 1 b of inverter 1 , and feeds a signal showing the detected value to control circuit 4 .
- Capacitor C 1 is connected between terminals 1 a and 1 b of inverter 1 , and smoothes and stabilizes DC voltage Ea between terminals 1 a and 1 b .
- Inverter 1 is controlled by output signals ⁇ 1 , . . . from driver DR 1 , to convert DC voltage Ea between positive voltage terminal 1 a and negative voltage terminal 1 b into an AC fundamental wave voltage Va, and then, and outputs the converted voltage between AC terminals 1 c and 1 d.
- Inverter 2 has a positive voltage terminal 2 a connected to a positive voltage terminal T 3 through current detector IS 2 , and a negative voltage terminal 2 b connected to negative voltage terminal T 4 .
- Current detector IS 2 detects a DC current that flows between inverter 2 and DC circuit 6 , and feeds a signal showing the detected value to control circuit 4 .
- Voltage detector VS 2 detects DC voltage Eb between terminals 2 a and 2 b of inverter 2 , and feeds a signal showing the detected value to control circuit 4 .
- Capacitor C 2 is connected between terminals 2 a and 2 b of inverter 2 , and smoothes and stabilizes DC voltage Eb between terminals 2 a and 2 b .
- Inverter 2 is controlled by output signals ⁇ 11 , . . . of driver DR 2 , converts DC voltage Eb between positive voltage terminal 2 a and negative voltage terminal 2 b into an AC fundamental wave voltage Vb, and then outputs the converted voltage between AC terminals 2 c and 2 d.
- Control circuit 4 is formed of a microcomputer, for example, and generates control signals ⁇ 1 , . . . for inverters 1 and 2 based on output signals from voltage detectors VS 1 , VS 2 and current detectors IS 1 , IS 2 . Based on the detection results of voltage detectors VS 1 and VS 2 , control circuit 4 sets pulse widths ⁇ and ⁇ of two AC fundamental wave voltages Va and Vb such that effective values of AC fundamental wave voltages Va and Vb generated in inverters 1 and 2 coincide with each other. Furthermore, control circuit 4 sets a phase difference ⁇ between two AC fundamental wave voltages Va and Vb such that desired DC power flows from one selected from DC circuits 5 and 6 to the other one of DC circuits 5 and 6 . Furthermore, control circuit 4 generates control signals ⁇ 1 , . . . for inverters 1 and 2 based on pulse widths ⁇ and ⁇ and phase difference ⁇ that have been set.
- Driver DR 1 amplifies control signals ⁇ 1 , . . . for inverter 1 and supplies the amplified signals to inverter 1 .
- Driver DR 2 amplifies control signals ⁇ 11 , . . . for inverter 2 and supplies the amplified signals to inverter 2 .
- FIG. 2 is a circuit diagram showing the configurations of inverters 1 and 2 .
- inverter 1 includes IGBTs (Insulated Gate Bipolar Transistor) Q 1 to Q 4 and diodes D 1 to D 4 .
- IGBTs Q 1 and Q 2 have collectors each connected to positive voltage terminal 1 a , gates receiving control signals ⁇ 1 and ⁇ 2 , respectively, and emitters connected to AC terminals 1 c and 1 d , respectively.
- IGBTs Q 3 and Q 4 have collectors connected to AC terminals 1 c and 1 d , respectively, gates receiving control signals / ⁇ 1 and / ⁇ 2 , respectively, and emitters each connected to negative voltage terminal 1 b .
- Diodes D 1 to D 4 are connected in anti-parallel to IGBTs Q 1 to Q 4 , respectively.
- Each of control signals ⁇ 1 , / ⁇ 1 , ⁇ 2 , and / ⁇ 2 is a PWM (Pulse Width Modulation) signal and also is a rectangular wave signal having a predetermined frequency (for example, 10 kHz).
- Control signals / ⁇ 1 and / ⁇ 2 are obtained by inverting control signals ⁇ 1 and ⁇ 2 , respectively. Therefore, IGBTs Q 1 and Q 3 are not simultaneously turned on, and IGBTs Q 2 and Q 4 are not simultaneously turned on.
- IGBTs Q 1 and Q 4 When IGBTs Q 1 and Q 4 are turned on, a current flows from positive voltage terminal 1 a through IGBT Q 1 , reactor L 1 , primary winding 3 a and IGBT Q 4 into negative voltage terminal 1 b . Furthermore, when IGBTs Q 2 and Q 3 are turned on, a current flows from positive voltage terminal 1 a through IGBT Q 2 , primary winding 3 a , reactor L 1 , and IGBT Q 3 into negative voltage terminal 1 b . Accordingly, IGBTs Q 1 to Q 4 are controlled by control signals ⁇ 1 , / ⁇ 1 , ⁇ 2 , and / ⁇ 2 to be turned on or off, so that AC power can be supplied to primary winding 3 a.
- inverter 2 includes IGBTs Q 11 to Q 14 and diodes D 11 to D 14 .
- IGBTs Q 11 and Q 12 have collectors each connected to positive voltage terminal 2 a , gates receiving control signals ⁇ 11 and ⁇ 12 , respectively, and emitters connected to AC terminals 2 c and 2 d , respectively.
- IGBTs Q 13 and Q 14 have collectors connected to AC terminals 2 c and 2 d , respectively, gates receiving control signals / ⁇ 11 and / ⁇ 12 , respectively, and emitters each connected to negative voltage terminal 2 b .
- Diodes D 11 to D 14 are connected in anti-parallel to IGBTs Q 11 to Q 14 , respectively.
- Control signals ⁇ 11 , / ⁇ 11 , ⁇ 12 , and / ⁇ 12 are PWM signals and also are rectangular wave signals having the same frequencies (for example, 10 kHz) as those of control signals ⁇ 1 , / ⁇ 1 , ⁇ 2 , and / ⁇ 2 , respectively.
- Control signals / ⁇ 11 and / ⁇ 12 are obtained by inverting control signals ⁇ 11 and ⁇ 12 , respectively. Accordingly, IGBTs Q 11 and Q 13 are not simultaneously turned on, and IGBTs Q 12 and Q 14 are not simultaneously turned on.
- IGBTs Q 11 and Q 14 When IGBTs Q 11 and Q 14 are turned on, a current flows from positive voltage terminal 2 a through IGBT Q 11 , reactor L 2 , secondary winding 3 b , and IGBT Q 14 into negative voltage terminal 2 b . Furthermore, when IGBTs Q 12 and Q 13 are turned on, a current flows from positive voltage terminal 2 a through IGBT Q 12 , secondary winding 3 b , reactor L 2 , and IGBT Q 13 into negative voltage terminal 2 b . Accordingly, IGBTs Q 11 to Q 14 are controlled by control signals ⁇ 11 , / ⁇ 11 , ⁇ 12 , and / ⁇ 12 to be turned on or off, so that AC power can be supplied to secondary winding 3 b.
- the effective values of AC fundamental wave voltages Va and Vb are caused to coincide with each other and phase difference ⁇ between AC fundamental wave voltages Va and Vb are controlled, so that DC power can be supplied from DC circuit 5 through inverters 1 and 2 to DC circuit 6 , and also that DC power can be supplied from DC circuit 6 through inverters 2 and 1 to DC circuit 5 .
- FIG. 3 is a block diagram showing a part of control circuit 4 that is related to generation of control signals ⁇ 1 , / ⁇ 1 , ⁇ 2 , / ⁇ 2 , ⁇ 11 , / ⁇ 11 , ⁇ 12 , and / ⁇ 12 . It is to be noted that FIG. 3 shows a part used when DC power is supplied from DC circuit 5 to DC circuit 6 . In addition, in the case where DC power is supplied from DC circuit 6 to DC circuit 5 , voltage detectors VS 1 and VS 2 are replaced with each other while current detectors IS 2 and IS 1 are replaced with each other, for example, by a switching circuit.
- control circuit 4 includes a pulse width setting unit 10 , a voltage command unit 11 , subtractors 12 and 14 , a voltage controller 13 , a current controller 15 , and a signal generation unit 16 .
- pulse width setting unit 10 Based on DC voltage Ea between terminals T 1 and T 2 that is detected by voltage detector VS 1 and DC voltage Eb between terminals T 3 and T 4 that is detected by voltage detector VS 2 , pulse width setting unit 10 sets pulse widths ⁇ and ⁇ (rad) of AC fundamental wave voltages Va and Vb such that the effective values of AC fundamental wave voltages Va and Vb output from inverters 1 and 2 coincide with each other.
- FIGS. 4( a ) to 4( d ) each are a diagram showing the relation between AC fundamental wave voltages Va and Vb.
- ⁇ V shows a differential voltage between Va and Vb.
- I shows a current that is caused to flow by differential voltage ⁇ V between Va and Vb.
- VA and VB are effective values of Va and Vb, respectively.
- the pulse width (in this case, ⁇ ) of the AC fundamental wave voltage (in this case, Vb) corresponding to a higher DC voltage (for example, Eb) of two DC voltages Ea and Eb is narrowed, to cause effective values VA and VB of AC fundamental wave voltages Va and Vb to coincide with each other.
- examples of the method for improving a power factor include three methods shown in FIGS. 5( a ) to 5( c ) .
- the phase of Va is fixed and the phase of Vb is delayed by ⁇ , as shown in FIG. 5( a ) .
- the power factors of Va, Vb and I each exhibit cos( ⁇ /2) that is excellent.
- AC fundamental wave voltages Va and Vb are expressed by the following equations (1) and (2), respectively.
- ⁇ represents a phase difference (rad) between Va and Vb.
- ⁇ t 2 ⁇ ft(rad).
- Va (4/ ⁇ ) Ea ⁇ sin( ⁇ /2) ⁇ sin( ⁇ t+ ⁇ / 2)
- Vb (4/ ⁇ ) Eb ⁇ sin( ⁇ /2) ⁇ sin( ⁇ t ⁇ / 2) (2)
- FIG. 6( b ) shows the case where ⁇ >0 and the phase of Va is advanced more than Vb is. If ⁇ 0, the phase of Vb is advanced more than Va is.
- voltage command unit 11 generates a target voltage EbT of DC voltage Eb.
- Subtractor 12 calculates a deviation between target voltage EbT and DC voltage Eb that is detected by voltage detector VS 2 .
- Voltage controller 13 generates a current command value IT of the value obtained in accordance with the deviation between EbT and Eb calculated by subtractor 12 . It is to be noted that this current command value IT is limited by the limiter to a prescribed value or less.
- Subtractor 14 calculates a deviation between current command value IT generated in voltage controller 13 and current I detected by current detector IS 2 .
- Current controller 15 generates phase difference ⁇ of the value obtained in accordance with the deviation between IT and I calculated by subtractor 14 . It is to be noted that this phase difference ⁇ is limited by the limiter to a prescribed value or less.
- signal generation unit 16 Based on pulse widths ⁇ and ⁇ set by pulse width setting unit 10 and phase difference ⁇ generated in current controller 15 , signal generation unit 16 generates control signals ⁇ 1 , / ⁇ 1 , ⁇ 2 , / ⁇ 2 for inverter 1 and control signals ⁇ 11 , / ⁇ 11 , ⁇ 12 , and / ⁇ 12 for inverter 2 .
- a sawtooth waveform signal ST having a frequency that is twice as high as the frequency of AC fundamental wave voltage Va is generated. It is assumed that sawtooth waveform signal ST oscillates with amplitudes between 0 and ⁇ , and one period of sawtooth waveform signal ST is defined as ⁇ .
- AC fundamental wave voltage Va reaches Ea in the time period during which each of control signals ⁇ 1 and / ⁇ 2 is at an “H” level.
- sawtooth waveform signal ST and a first reference signal S 1 ⁇ /2+( ⁇ /2 ⁇ /2) cross each other in each period.
- control signal ⁇ 1 is raised from the “L” level to the “H” level.
- control signal ⁇ 1 is lowered from the “H” level to the “L” level.
- sawtooth waveform signal ST and a second reference signal S 2 ⁇ /2+( ⁇ /2+ ⁇ /2) cross each other in each period.
- control signal / ⁇ 2 is raised from the “L” level to the “H” level.
- control signal / ⁇ 12 is lowered from the “H” level to the “L” level.
- sawtooth waveform signal ST having a frequency that is twice as high as the frequency of AC fundamental wave voltage Va
- a first reference signal S 1 ⁇ /2+( ⁇ /2 ⁇ /2)
- control signal ⁇ 1 only has to be generated based on the cross point between ST and S 1
- control signal / ⁇ 2 only has to be generated based on the cross point between ST and S 2 .
- Sawtooth waveform signal ST having a frequency that is twice as high as the frequency of AC fundamental wave voltage Va is generated. It is assumed that sawtooth waveform signal ST oscillates with amplitudes between 0 and ⁇ , and one period of sawtooth waveform signal ST is defined as ⁇ .
- the phase of control signal ⁇ 1 is advanced by ⁇ from control signal ⁇ 11 .
- the angle width in which control signal ⁇ 1 is at an “H” level and control signal ⁇ 11 is at an “L” level is defined as a phase difference ⁇ .
- the center angle of the angle width in which control signal ⁇ 1 is at an “H” level and control signal ⁇ 11 is at an “L” level coincides with the angle at which sawtooth waveform signal ST is ⁇ /2.
- sawtooth waveform signal ST having a frequency that is twice as high as the frequency of AC fundamental wave voltage Va
- a first reference signal S 1 ⁇ /2+( ⁇ /2)
- control signal ⁇ 1 only has to be generated based on the cross point between ST and S 1
- control signal ⁇ 11 only has to be generated based on the cross point between ST and S 3 .
- control signal ⁇ 1 are determined based at the cross point between ST and S 1 .
- the leading edge and the trailing edge of control signal / ⁇ 2 are determined based on the cross point between ST and S 2 .
- the leading edge and the trailing edge of control signal ⁇ 11 are determined based on the cross point between ST and S 3 .
- the leading edge and the trailing edge of control signal / ⁇ 12 are determined based on the cross point between ST and S 4 .
- the leading edge is determined at the cross point in the odd-numbered period
- the trailing edge is determined at the cross point in the even-numbered period.
- Control signals ⁇ 1 , / ⁇ 2 , ⁇ 11 , and / ⁇ 12 are inverted to thereby achieve control signals / ⁇ 1 , ⁇ 2 , / ⁇ 11 , and ⁇ 12 , respectively.
- pulse width ⁇ of each of control signals ⁇ 1 , / ⁇ 1 , ⁇ 2 , and / ⁇ 2 is fixed at ⁇ while pulse width ⁇ of each of control signals ⁇ 11 , / ⁇ 11 , ⁇ 12 , and / ⁇ 12 is fixed at ⁇ .
- FIGS. 9( a ) to 9( g ) each are a time chart showing the method of generating control signals ⁇ 1 , ⁇ 2 , ⁇ 11 , and / ⁇ 12 in the case where Ea>Eb.
- control signal ⁇ 1 is raised at each odd-numbered cross point between ST and S 1
- control signal ⁇ 1 is lowered at each even-numbered cross point between ST and S 1
- Control signal / ⁇ 1 is obtained by inverting control signal ⁇ 1 .
- control signal / ⁇ 2 is raised at each odd-numbered cross point between ST and S 2 , and control signal / ⁇ 2 is lowered at each even-numbered cross point between ST and S 2 .
- Control signal ⁇ 2 is obtained by inverting control signal / ⁇ 2 .
- AC fundamental wave voltage Va reaches +Ea when control signals ⁇ 1 and / ⁇ 2 each are at the “H” level, reaches ⁇ Ea when control signals ⁇ 1 and / ⁇ 2 each are at the “L” level, and reaches 0V when one of control signals ⁇ 1 and / ⁇ 2 is at the “H” level and the other of control signals ⁇ 1 and / ⁇ 2 is at the “L” level.
- control signal ⁇ 11 is raised at each odd-numbered cross point between ST and S 3 , and control signal ⁇ 11 is lowered at each even-numbered cross point between ST and S 3 .
- Control signal / ⁇ 11 is obtained by inverting control signal ⁇ 11 .
- control signal / ⁇ 12 is raised at each odd-numbered cross point between ST and S 4 , and control signal / ⁇ 12 is lowered at each even-numbered cross point between ST and S 4 .
- Control signal ⁇ 12 is obtained by inverting control signal / ⁇ 12 .
- AC fundamental wave voltage Vb reaches +Ea when control signals ⁇ 11 and / ⁇ 12 each are at the “H” level, and reaches ⁇ Ea when control signals ⁇ 11 and / ⁇ 12 each are at the “L” level.
- the effective values of AC fundamental wave voltages Va and Vb coincide with each other, so that the power factor is maintained at a relatively higher level. Since the phase of AC fundamental wave voltage Va is advanced by ⁇ from the phase of AC fundamental wave voltage Vb, DC power is supplied from inverter 1 to inverter 2 .
- the pulse width of AC fundamental wave voltage Va or Vb corresponding to a higher DC voltage of DC voltages Ea and Eb is narrowed to cause the effective values of Va and Vb to coincide with each other.
- phase difference ⁇ between AC fundamental wave voltages Va and Vb is set in accordance with the value and the direction of the current that is desired to flow. Accordingly, even when DC voltages Ea and Eb greatly fluctuate, DC power can be stably transmitted and received between DC circuits 5 and 6 .
- DC power can be supplied from DC circuit 5 (or 6 ) to DC circuit 6 (or 5 ).
- DC power can be supplied from the Ea side to the Eb side even when Ea lowers to 80V and Eb rises to 120V.
- Ea 100V
- Eb 70V to 80V
- the DC power transmitted and received between DC circuits 5 and 6 can be controlled linearly in a positive and negative range, and further, the flow direction of the power can be reversed instantaneously within several cosecs.
- two DC circuits 5 and 6 with relatively large voltage fluctuation width are cooperated while being insulated from each other, so that a bidirectional smooth power interchange can be implemented, and also, the problem related to safety and EMI and the problem related to a withstand voltage can be solved by grounding isolation.
- pulse width ⁇ or ⁇ of AC fundamental wave voltage Va or Vb corresponding to a higher DC voltage of DC voltages Ea and Eb is narrowed to cause the effective values of Va and Vb to coincide with each other, but the present invention is not limited thereto.
- the pulse width of AC fundamental wave voltage Va. or Vb may be narrowed such that the difference between the effective values of Va and Vb is equal to or less than a prescribed value.
- pulse width ⁇ or ⁇ of AC fundamental wave voltage Va or Vb may be narrowed such that the ratio of the difference between the effective values of Va and Vb to the effective value of Va or Vb is equal to or less than several %.
- voltage detector VS 1 detects DC voltage Ea between terminals T 1 and T 2
- voltage detector VS 2 detects DC voltage Eb between terminals T 3 and T 4
- DC voltages Ea and Eb may be detected by other methods.
- the output AC voltages of inverters 1 and 2 may be captured in control circuit 4 through a signal transformer, the peak values of the captured AC voltages may be sampled, and DC voltages Ea and Eb may be detected indirectly from the sampled peak values.
- two reactors L 1 and L 2 are provided in the present first embodiment, one of two reactors L 1 and L 2 may be eliminated, or two reactors L 1 and L 2 may be eliminated in the case where insulated transformer 3 has a leakage inductance.
- control signals ⁇ 1 , / ⁇ 1 , ⁇ 2 , and / ⁇ 2 are raised at the cross points between sawtooth waveform signal ST and reference signals S 1 to S 4 , respectively, in each odd-numbered period of sawtooth waveform signal ST, and control signals ⁇ 1 , / ⁇ 1 , ⁇ 2 , and / ⁇ 2 are raised at the cross points between sawtooth waveform signal ST and reference signals S 1 to S 4 , respectively, in each even-numbered period of sawtooth waveform signal ST.
- the present invention is not limited to this, but the information related to the cross points between sawtooth waveform signal ST and reference signals S 1 to S 4 in each odd-numbered or even-numbered period may be stored, and control signals ⁇ 1 , / ⁇ 1 , ⁇ 2 , and / ⁇ 2 may be generated based on the stored information.
- control signals ⁇ 1 , / ⁇ 1 , ⁇ 2 , and / ⁇ 2 may be raised at the cross points between sawtooth waveform signal ST and reference signals S 1 to S 4 , respectively, in each odd-numbered period of sawtooth waveform signal ST.
- the information related to these cross points may be stored, and control signals ⁇ 1 , / ⁇ 1 , ⁇ 2 , and / ⁇ 2 may be raised in each even-numbered period of sawtooth waveform signal ST based on the stored information.
- the waveforms of AC fundamental wave voltages Va and Vb can be rendered positively and negatively symmetrical, and bias magnetism in insulated transformer 3 can be prevented from occurring.
- FIG. 10 is a block diagram showing the configuration of a smart network according to the second embodiment of the present invention.
- this smart network includes: a bidirectional insulated DC/DC converter 20 having a configuration described in the first embodiment; and two DC power systems 21 and 22 .
- DC power system 21 includes a commercial AC power supply 30 , a solar photovoltaic power generator 31 , a wind power generator 32 , a PWM converter 33 , converters 34 and 35 , a DC bus 36 , a charge/discharge controlling converters 37 and 38 , an LiPo battery 39 , an electric double layer capacitor 40 , and a load 41 .
- PWM converter 33 converts the commercial AC power from commercial AC power supply 30 into DC power having a prescribed DC voltage Ea (for example, 300V), and supplies the converted power to DC bus 36 . Furthermore, when the commercial AC power becomes insufficient, PWM converter 33 converts the DC power from DC bus 36 into AC power having a prescribed voltage at a commercial frequency, and supplies the converted power to commercial AC power supply 30 .
- Ea for example, 300V
- Solar photovoltaic power generator 31 converts light energy from the sun into DC power.
- Converter 34 converts the DC power generated in solar photovoltaic power generator 31 into DC power having a prescribed DC voltage Ea, and supplies the converted power to DC bus 36 .
- Wind power generator 32 converts the wind power into DC power.
- Converter 35 converts the DC power generated in wind power generator 32 into DC power having a prescribed DC voltage Ea, and supplies the converted power to DC bus 36 .
- charge/discharge controlling converter 37 When DC power is excessive in DC power system 21 , charge/discharge controlling converter 37 extracts DC power from DC bus 36 and stores the extracted DC power in LiPo battery 39 . When DC power is insufficient in DC power system 21 , charge/discharge controlling converter 37 extracts DC power from LiPo battery 39 and supplies the extracted DC power to DC bus 36 .
- charge/discharge controlling converter 38 extracts DC power from DC bus 36 and stores the extracted DC power in electric double layer capacitor 40 .
- charge/discharge controlling converter 38 extracts DC power from electric double layer capacitor 40 and stores the extracted DC power in DC bus 36 .
- Load 41 represents a general house, an office, plant facilities, electric vehicle charging facilities, and the like, and consumes DC power from DC bus 36 .
- DC power system 22 which has the same configuration as that of DC power system 21 , includes a DC bus 23 maintained at a prescribed DC voltage Eb (for example, 1000V).
- Bidirectional insulated DC/DC converter 20 which has been described in the first embodiment, transmits and receives DC power between DC buses 36 and 23 .
- DC bus 36 includes a DC positive bus and a DC negative bus connected to terminals T 1 and T 2 , respectively.
- DC bus 23 includes a DC positive bus and a DC negative bus connected to terminals T 3 and T 4 , respectively.
- Bidirectional insulated DC/DC converter 20 serves to narrow the pulse width of AC fundamental wave voltage Vb corresponding to a higher DC voltage (Eb in the present second embodiment) of DC voltages Ea and Eb to thereby cause the effective values of Va and Vb to coincide with each other.
- bidirectional insulated DC/DC converter 20 sets phase difference ⁇ between AC fundamental wave voltages Va and Vb in accordance with the value and the direction of the current that is desired to flow.
- the present smart network also has a function of an uninterruptible power supply system.
- two DC power systems 21 and 22 are coupled by bidirectional insulated DC/DC converter 20 . Accordingly, even when DC voltages Ea and Eb on DC power systems 21 and 22 greatly vary, DC power can be stably transmitted and received between DC power systems 21 and 22 .
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Inverter Devices (AREA)
- Direct Current Feeding And Distribution (AREA)
- Dc-Dc Converters (AREA)
Abstract
Description
Va=(4/π)Ea·sin(α/2)·sin(ωt+θ/2) (1)
Vb=(4/π)Eb·sin(β/2)·sin(ωt−θ/2) (2)
S1=π/2+(−θ/2+π/2−α/2)[rad]
S2=π/2+(−θ/2−π/2+α/2)[rad]
S3=π/2+(θ/2+π/2−β/2)[rad]
S4=π/2+(θ/2−π/2+β/2)[rad]
Claims (11)
α=2 sin−1(Eb/Ea) and β=π when Ea>Eb, and
α=π and β=2 sin−1(Ea/Eb) when Eb>Ea.
S1=π/2+(−θ/2+π/2−α/2) that is a first reference signal,
S2=π/2+(−θ/2−π/2+α/2) that is a second reference signal,
S3=π/2+(θ/2+π/2−β/2) that is a third reference signal, and
S4=π/2+(θ/2−π/2+β/2) that is a fourth reference signal,
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JP2013217170 | 2013-10-18 | ||
JP2013-217170 | 2013-10-18 | ||
PCT/JP2014/073869 WO2015056503A1 (en) | 2013-10-18 | 2014-09-10 | Bidirectional insulated dc/dc converter and smart network using same |
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US10044281B2 true US10044281B2 (en) | 2018-08-07 |
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JP (1) | JP6171022B2 (en) |
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JP6307368B2 (en) * | 2014-06-27 | 2018-04-04 | 新電元工業株式会社 | DC / DC converter control device and control method thereof |
CN109196766B (en) * | 2016-05-31 | 2020-09-29 | 东芝三菱电机产业系统株式会社 | Bidirectional insulation type DC/DC converter and smart power grid |
JP6782474B2 (en) * | 2017-01-31 | 2020-11-11 | 独立行政法人国立高等専門学校機構 | Thermoelectric conversion element output control device |
JP2019022357A (en) * | 2017-07-19 | 2019-02-07 | 矢崎総業株式会社 | Dc-dc converter |
CN107565834B (en) * | 2017-07-25 | 2020-03-24 | 全球能源互联网研究院有限公司 | Control method and device for alternating current-direct current conversion circuit |
CN117099294A (en) * | 2021-04-26 | 2023-11-21 | 三菱电机株式会社 | Power conversion device |
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JP6171022B2 (en) | 2017-07-26 |
KR101862951B1 (en) | 2018-05-30 |
US20160233778A1 (en) | 2016-08-11 |
KR20160078353A (en) | 2016-07-04 |
EP3059845A4 (en) | 2017-06-28 |
EP3059845A1 (en) | 2016-08-24 |
WO2015056503A1 (en) | 2015-04-23 |
JPWO2015056503A1 (en) | 2017-03-09 |
CN105637752B (en) | 2018-06-22 |
CN105637752A (en) | 2016-06-01 |
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